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Improve ARP logging.

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r344504 added an extra ARP_LOG() call in case of an if_output() failure.
It turns out IPv4 can be noisy. In order to not spam the console by default:
(a) add a counter for these events so people can keep better track of how
    often it happens, and
(b) add a sysctl to select the default ARP_LOG log level and set it to
    INFO avoiding the one (the new) DEBUG level by default.

Claim a spare (1st one after 10 years since the stats were added) in order
to not break netstat from FreeBSD 12->13 updates in the future.

Reviewed by:		karels
Differential Revision:	https://reviews.freebsd.org/D19490
This commit is contained in:
Bjoern A. Zeeb 2019-03-09 01:12:59 +00:00
parent 244e58a2df
commit b25d74e06c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=344954
3 changed files with 14 additions and 3 deletions
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3
sys/net/if_arp.h
View File

@ -105,8 +105,9 @@ struct arpstat {
uint64_t rxrequests; /* # of ARP requests received by this host. */
uint64_t rxreplies; /* # of ARP replies received by this host. */
uint64_t received; /* # of ARP packets received by this host. */
uint64_t txerrors; /* # of ARP requests failed to send. */
uint64_t arp_spares[4]; /* For either the upper or lower half. */
uint64_t arp_spares[3]; /* For either the upper or lower half. */
/* Abnormal event and error counting: */
uint64_t dropped; /* # of packets dropped waiting for a reply. */
uint64_t timeouts; /* # of times with entries removed */

13
sys/netinet/if_ether.c
View File

@ -161,8 +161,15 @@ SYSCTL_PROC(_net_link_ether_inet, OID_AUTO, garp_rexmit_count,
"Number of times to retransmit GARP packets;"
" 0 to disable, maximum of 16");
VNET_DEFINE_STATIC(int, arp_log_level) = LOG_INFO; /* Min. log(9) level. */
#define V_arp_log_level VNET(arp_log_level)
SYSCTL_INT(_net_link_ether_arp, OID_AUTO, log_level, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(arp_log_level), 0,
"Minimum log(9) level for recording rate limited arp log messages. "
"The higher will be log more (emerg=0, info=6 (default), debug=7).");
#define ARP_LOG(pri, ...) do { \
if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \
if ((pri) <= V_arp_log_level && \
ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \
log((pri), "arp: " __VA_ARGS__); \
} while (0)
@ -428,9 +435,11 @@ arprequest_internal(struct ifnet *ifp, const struct in_addr *sip,
m_clrprotoflags(m); /* Avoid confusing lower layers. */
error = (*ifp->if_output)(ifp, m, &sa, &ro);
ARPSTAT_INC(txrequests);
if (error)
if (error) {
ARPSTAT_INC(txerrors);
ARP_LOG(LOG_DEBUG, "Failed to send ARP packet on %s: %d\n",
if_name(ifp), error);
}
return (error);
}

1
usr.bin/netstat/inet.c
View File

@ -1044,6 +1044,7 @@ arp_stats(u_long off, const char *name, int af1 __unused, int proto __unused)
xo_emit("\t" m, (uintmax_t)arpstat.f, pluralies(arpstat.f))
p(txrequests, "{:sent-requests/%ju} {N:/ARP request%s sent}\n");
p(txerrors, "{:sent-failures/%ju} {N:/ARP request%s failed to sent}\n");
p2(txreplies, "{:sent-replies/%ju} {N:/ARP repl%s sent}\n");
p(rxrequests, "{:received-requests/%ju} "
"{N:/ARP request%s received}\n");